How could God be given a specific sexual connotation if in the Bible he is presented with both male and female characteristics? Should we not address him also as "Mother"?
The concept of God as “Father” has always existed in the Old Testament, but it was Jesus who emphasized this title, manifesting himself as the "Son". It was Jesus who so lovingly referred to God with the Aramaic word "Abba", a term of endearment similar to "Daddy". Jesus also entrusted his disciples with the Lord's Prayer, which has been passed down through the Gospel of Luke (11:2-4) and Matthew (6:9-13), although the liturgical tradition of Church has always used the text of the latter.
The Catechism of the Catholic Church notes that “God is Father in an unheard-of sense: he is Father not only in being Creator; he is eternally Father in relation to his only Son, who is eternally Son only in relation to his Father: ‘No one knows the Son except the Father, and no one knows the Father except the Son and any one to whom the Son chooses to reveal him’” (239).
It is also true, however, that the Bible often represents God with feminine characteristics as a sign of his spontaneous, instinctive, and absolute love.
Cardinal Gianfranco Ravasi, in an interview with the newspaper "Avvenire" in December 2005, stated that "at least sixty adjectives referring to God in the Bible are feminine” and that "there are clearly maternal characteristics to describe God”. We find two examples in the book of Isaiah: "Can a woman forget her sucking child, that she should have no compassion on the son of her womb? Even these may forget, yet I will not forget you” (49:15), and "As one whom his mother comforts, so will I comfort you" (66:13).
Joseph Ratzinger, in the book-length interview titled God and the World: A Conversation with Peter Seewald (Ballantine Books, 2002), explained that the Hebrew “rahamim”, originally meaning 'womb', is the term that is used to represent the compassion of God toward man:
"The womb is the most concrete expression of the intimate relationship between two beings and the delicate attention to the weak and dependent creature. Body and soul is fully guarded in the womb of the mother; therefore, figurative language and our own body give us an understanding of the deep love of God for man.
This should not, however, lessen the "fatherly face" of God; it must be remembered that the word 'Father' is still a metaphor to express the nature of divine love. In his first book in the Jesus of Nazareth series, Pope Benedict XVI writes that despite the great metaphors about a mother’s love, “mother” is not a name with which we address God. The Holy Father further mentions that, in fact, “God alone is Father”, and “the language of prayer in the whole Bible remains normative for us.” The image of the father was and is adequate to express the otherness between Creator and creature and the sovereignty of his creative act.
In the book Questions of Faith (Mondadori, 2010), Ravasi reminds us that when referring to God as a Father we must always remember that it is an anthropomorphism – a symbol that expresses the ineffable divine mystery and to represent the reality of the Unknown. The Bible, being the living Word of God, favors the fatherly face of God due to the cultural conditioning specific to the time the Bible was written. It is permissible, therefore, to resize some overly literal readings of the 'masculinity' of God without denying the values it expresses.
On this note, Cardinal Ratzinger explains in God and the World that while widespread religions in the area around Israel believed in “couple deities” – a male deity and a female deity – monotheism, on the contrary, excludes pairs of divinity and instead addresses the people of Israel as the female spouse of God. Therefore, history is told as a love story between God and mankind just like a love story between a man and his wife. From this point of view, the female image is projected onto Israel and the Church, and ultimately personified in a particular way in Mary. Secondly, when maternal metaphors are used in reference to the divine, they give way to a pantheistic model of divinity wherein the concept of creation is replaced by emanation (divinity coming forth from divinity). On the contrary, the God represented in paternal terms creates by way of the Word, and it is precisely from this point that the specific distinction between creation and creature derives.